As attachment devices, screws are known with nuts screwed onto a threaded pin of the screw, and screws that are screwed into a threaded borehole. The connecting parts to be attached to each other are arranged between the screw head and the nut screwed on to the threaded pin. However, screw connections have a drawback in that they require a relatively time-consuming attachment process. Thus, for example a screw has to be turned multiple times until it is screwed in far enough. With through screws it is necessary to provide the pin end with a nut, and for pin screws often the other pin end also. When there is a plurality of screw connections, the cumulative assembly time is enormous.
Additionally, clips are known as generic attachment devices. These have a fastener with a head with a head contact surface. A pin extends out from the head along a longitudinal axis. The pin has an attachment end with a contact surface, which lies opposite the head contact surface. The connection parts to be connected with the attachment device are arranged between the head contact surface and the contact surface of the pin, with the pin engaging into openings made in the connecting pieces. With this, provision is made that the contact surface is configured on a spring-loaded element of the pin. Spring force puts tension on the element away from the longitudinal axis of the pin. This makes it possible to guide the pin of the connector through the openings of the connection pieces, with the spring-loaded element moving against the spring force to the longitudinal axis of the pin, thus reducing the circumference of the pin. After passing through the opening, the spring-loaded element moves back into its original setting, thereby expanding the circumference of the pin. By this means the pin is prevented from being able to be pulled back through the opening. What is disadvantageous with such an attachment device is that the distance between the head contact surface and the contact surface in the initial setting of the spring-loaded element is preset in fixed fashion and thus the connection force acting on the connecting pieces to be joined is preset in fixed fashion.